Is there any way to make a simple LAN port tester that can plug into an ethernet port and check for connectivity. I dont want to use the cable testers as it require both ends of a cable to be plugged in. I just want to test signal to a port.
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1\$\begingroup\$ network layer. i just want to have maybe a small kit that have something with a green light that lights up if there is a signal. \$\endgroup\$– y.daJan 17, 2018 at 3:33
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2\$\begingroup\$ @Sparky256 that last part is BS. Unless you mean: if your computer belongs to a bank or government agency. \$\endgroup\$– user253751Jan 17, 2018 at 4:30
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2\$\begingroup\$ @Sparky256 Your Ethernet chip can always see packet headers, otherwise how would it know where the packets should go? And websites cannot read your MAC address while running wireshark. I've also accessed my own bank's website while running Wireshark. If your bank somehow does do that, you should switch banks because they are hacking your computer. \$\endgroup\$– user253751Jan 17, 2018 at 4:43
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2\$\begingroup\$ @Sparky256 They are accessing information on your PC that is not normally meant to be accessible to them; that's "hacking" by my standards. (Their protection is useless anyway. You can bypass it by using a second computer as a router, and running Wireshark on that computer) \$\endgroup\$– user253751Jan 17, 2018 at 5:14
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1\$\begingroup\$ Government certs to read mac address, o.m.g. take your tin foil hat some where else. \$\endgroup\$– PasserbyJan 17, 2018 at 6:42
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A simple tester is nothing more than a Loopback jack. You tie the tx pairs to the rx pairs of a rj45 Ethernet jack and plug it into the network adapter. The link light should turn on, as well as the activity light. This is enough for the network equipment to negotiate a speed and connection, but would not be useful for data.
Pictured is one for gigabit. 10/100 only need half of this.
Personally, I've used this to turn on the leds of my android tv box, that only turn on with the Ethernet connection.
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\$\begingroup\$ may i know, on what devices can we test this loopback.. because when i try on my pc, it works well. However, when i try it at the LAN port of an oscilloscope, it doesn't work at all. \$\endgroup\$– y.daJan 26, 2018 at 7:00
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\$\begingroup\$ Does the oscilloscope use Ethernet or is it using a rj45 for a different connection? This works on 10/100/1000 Ethernet \$\endgroup\$– PasserbyJan 26, 2018 at 14:24